Radioisotopes?

[fallen_6666]

Hello, I am a secondary school student currently taking grade 11 university chem. and I was wondering about the decay of atoms.

 

My first question is can regular atoms decay? , can isotopes decay? or is it just radioactive isotopes?

 

And is it just the radioactive ones that release energy? and what determines if alpha, beta, or gamma rays are going to be released.

 

Thank you.

[budullewraagh]

define "regular" with respect to atoms. the term isotope is used for any of the many atomic masses an atom of the same atomic number can have. radioactive elements release energy. depending on the element and number of neutrons different types of radiation occur. gamma is released by all atoms that decay, but in varying amounts from VERY little to quite a lot

[Gilded]

The decays (all of them?) are alpha, beta+, beta- and gamma. Look them up. For example in alpha decay, a heavy particle (a naked helium nuclei) of two neutrons and two protons is released, that's so heavy that it even won't penetrate your skin, nor a piece of paper. Beta is a bit more piercing, going through your skin but not through your body, but will be stopped by a sheet of aluminum. Gamma rays on the otherhand, pierce even thick blocks of concrete. Be careful with them.

[swansont]

My first question is can regular atoms decay? ' date=' can isotopes decay? or is it just radioactive isotopes?

 

And is it just the radioactive ones that release energy? and what determines if alpha, beta, or gamma rays are going to be released.

[/quote']

 

Only radioactive isotopes decay, by definition. If a nucleus decays, it is because it can be in a lower energy configuration - all decays spontaneously release energy.

 

In beta-minus decay, a neutron changes into a proton, and an electron and antineutrino are emitted. This happens because there are too many neutrons in the nucleus. In beta-plus decay, a proton is changed into a neutron, and a positron and neutrino are emitted, because the nucleus has too many protons (or too few neutrons, depending on how you want to look at it). For a given size of nucleus, there will be an optimal ratio of neutrons/protons. If you deviate from that, you tend to undergo beta decay.

 

Alpha decay happens because the nucleus is just too big. Too many protons, and the extra neutrons just can't compensate because the attractive force has a finite range, while the repulsive force has infinite range. Fission can happen spontaneously for the same reason, in some nuclei.

 

Gammas are emitted by nuclei in excited states.

 

All of this is modified by the shell nature of nuclear states. Just like there are stable configurations for atoms (noble gases) there are neutron and proton states that are particularly low in energy and thus more likely to be stable.

[Gilded]

Hey, does anyone know a site made with Java or Flash where you could click on different isotopes and then it shows their particle-structure and if it's an unstable isotope it goes through decay? I found one but I think it had only from H to oxygen. A list page would also be nice, with like "americium-241 | alpha decay into neptunium-239".

[swansont]

Hey, does anyone know a site made with Java or Flash where you could click on different isotopes and then it shows their particle-structure and if it's an unstable isotope it goes through decay? I found one but I think it had only from H to oxygen. A list page would also be nice, with like "americium-241 | alpha decay into neptunium-239".

 

It's not animated, but try this

[Gilded]

Gee, thanks mister. Pretty cool page, should help a bit.

 

Edit: Wow, can a single neutron really go through beta-decay and become H-1? How cool is that.

[budullewraagh]

thats good. i have a chart of the nuclides that's better tho